The invention relates to a portable apparatus for localized heating of the skin and intended mainly for therapeutic use, in particular for suppressing the disagreeable and even painful effects caused by the stings and bites of insects such as the hymenoptera (bees, wasps, hornets, ants, . . . ) and sea creatures such as weavers or sting fish, scorpion fish, jelly fish etc . . .
The venom of these creatures is destroyed by heat. An old known method consists in strongly heating the region attacked by a sting or bite by bringing the stung or bitten location close to a lighted cigarette or a hot object such as an iron heated to red heat.
This method is difficult to apply; it is incapable of heating the skin at exactly the desired location to the minimum temperature required and for a sufficient period of time to guarantee destroying the venom while avoiding running the risk of burning the skin.
At present there exists no small lightweight apparatus which is easily carried on the person and easily operated under all circumstances for providing localized heating of a region of the skin which has been bitten or stung by an insect or a sea creature having a thermolabile venom.
The main object of the invention is therefore to provide such a heating apparatus having the above-mentioned advantages and qualities.
It should be naturally understood that the use of apparatus of the invention is not limited to treating zones which have been stung or bitten and that the apparatus can be used wherever there is a need for localized heating of the skin for whatever reason.
Apparatuses are already known for the purpose of obtaining localized heating of the skin, as described, for example, in the following patent documents No. FR-A-1 139 096, U.S. Pat. Nos. 4,505,545, and 4,658,823.
Each of the apparatuses described in these three documents comprises a hollow elongate body having an open end, an electric lightbulb mounted in said body in the vicinity of its opposite end which is closed, and a reflector placed behind the lightbulb close to the closed end of the body. These apparatuses are used by putting the closed end into contact with the skin or in the vicinity of the skin while the lightbulb is powered with electricity and serves as a source of heat.
However, these three apparatuses are designed to be powered directly from the mains; the power specified for the bulbs is at least 15 W to 25 W and may be as much as several hundred watts. These apparatuses therefore cannot be carried on the person and cannot be powered from batteries or rechargeable batteries which are small enough to be easily transported. Further, the heat flux produced is not accurately determined. They are intended to heat the skin to a temperature which is not specified. The apparatus of above-mentioned U.S. Pat. No. 4,658,823 includes a thermostat but the thermostat is provided solely as a cut-off means for use when it is in danger of reaching a high limiting temperature value which could be dangerous for the user. This apparatus is intended for heating an ear as a whole, and it also includes openings of adjustable section to admit cold outside air without monitoring the temperature.
Temperature sensitive venoms are destroyed, depending on circumstances at temperatures lying between 50.degree. C. and 60.degree. C., which temperatures must be applied for a period of time lying between 20 seconds to 30 seconds for hymenoptera and between 1 minute to 3 minutes for sea creatures. Further, the venom begins to diffuse in the tissue immediately after it has been stung or bitten and it is desirable for the effective temperature to be applied to the skin without loss of time. In practice, once the apparatus has been put into place against the skin and has begun to heat the skin, it is desirable for the effective temperature of 50.degree. C. to 60.degree. C., to be reached in less than 1 minute.
If account is taken of the fact that the value of 60.degree. C. lies at the beginning of the temperature zone which the skin can withstand for a few moments only prior to starting to burn, it is quite clear that prior apparatuses do not have the characteristics which enable them to treat bites and stings reliably without burning the skin.
It may be observed that using a thermostat for the purpose of avoiding the danger of burning nevertheless suffers from the drawback of increasing the weight and the price of the apparatus. In order to ensure that the apparatus is portable and widely available, it is necessary to ensure, in addition, that it is as lightweight and as cheap as possible.